Conjoint polymerization product of dicarboxylic compounds and vinylic compounds



Patented Jan. 1, 1946 CONJOINT POLYMERIZATION PRODUCT OF DICARBOXYLIC COMPOUNDS NYLIC COMPOUNDS 1 Howard-L. Gerhart, Milwaukee, Wis assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania No Drawing. Application August .15, 1941,

SerialN0.-i07,010

1 Claim. (CL 260-36) The present invention relates to artificial resins and it has particular relation to such resins as are obtained by reacting substituted or unsubstituted ethylene 1, 3 dicarboxylic acids or anhydrides thereof with a polymerizable olefin.

One object of the invention is to provide a clear, hard, tough, stable and well plasticized resin of the above type which is relatively free from bubbles or cavities.

A second object 01 the invention is to provide a resinifying fluid material that can be cast, or can be employed as an investment median and formed into clear, hard, durable and tough bodies at low temperatures and with but little distor- These and other objects will be apparent from consideration of the following specification and the appended claim.

It has heretofore been proposed to heat an unsaturated dicarboxylic acid, such as maleic acid or its anhydride and a polymerizable olefin such as styrene to obtain polymerization products of white powdery character, which are soluble in acetone and dilute alkalies.

My copending application Serial No. 242,127, filed November 23, 1938 (now Patent 2,297,351

issued Sept. 29, 1942) is based upon the discovery that unsaturated dicarboxylic acids of the type of maleic acid, or maleic anhydride, or iumaric acid, or substituted maleic or fumaric acid and polymerizable olefins of the type of styrene will under the influence of actinic radiation react to form clear and hard resins which are relatively insoluble and substantially free of voids. These resins are well adapted for molding, cutting, pressing, or otherwise forming into bodies of great beauty. The resin-forming reaction may be carried out completely or at least in its final stages by casting the reacting mass in a suitable mold, thus obtainingdirectly the finally desired object.

However, considerable difliculty has been experienced in adequate plasticization of the resin AND- are quite generally of particular value as plas-, ticizers for resins oi the above-described type. The plasticizers may be either of open, chain or cyclic character, the type formulae of which are:

and

C I-fi 0 where R and x are organic radicals. Examples of the first-mentioned class of compounds include:

Diacetone alcohol CH: CHa("3-CH-C 0H Acetophenone cine-com methyl and ethyl acetone, methyl ethyl ketone, etc. are useful.

Carbonyl compounds represented by the generic cyclic formula include:

Isophorone Camphor Cyclohexanone Ortho and para methyl cyclohexanone and the like.

These plasticizers may be incorporated with the compounds undergoing resinification either before or after partial reaction and they may also be employed as solvents for the reactants.

The plasticizers may be employed as individuals or in admixture with each other or with other soluble compounds. The ratio of plasticizers may vary over a broad range, and may be as low as 10%, based upon the resin components, or as high as 50 or However, about 25 to 35% seems to be satisfactory.

The reaction to form the new compositions is typified by that between maleic acid or maleic acid anhydride and styrene. The two compounds, along with an appropriate plasticizer are simply admixed directly or are introduced into a solvent such as triacetin and are then caused to react by actinic irradiation at a temperature within the range of about 20 to 50 C. Irradiation of the reactants may be continued throughout the period of reaction, but it may be discontinued after the reaction has started. It is also possible to introduce a small amount (e. g. 1

' to of preliminarily irradiated reactants into the main batch and thus to obviate further irradiation.

Reaction may also be initiated by application of heat and after it has progressed sufliciently far, heating is discontinued. If very hard products are desired the mass may be finally heat treated at a suitable temperature (e. g. inc-200 C.) until the desired stage is reached. The reaction can be brought to completion within an hour or less, but by reducing the degree or time of irradiation it is possible to extend it over a period of several days.

The reaction product obtained from maleic anhydride and styrene may be represented by the formula:

where 2 represents the number of the foregoing groups in the molecule and is of variable value.

Since the reaction is general in character and applies to many unsaturated dicarboxylic acids or anhydrides; i. e., substituted maleic or fumaric acid and to many of the polymerizable olefins, the product may be represented by the type formula:

t t t. i.

where the groups R1, R2, R3, R4, R5, Re may be practically any of the possible substituent groups. Examples of a few of the possibilities include hydrogen and chlorine, carbonyl, carboxyl, alkyl, aromatic and the like groups. Examples of ethylene afi dicarboxylic acids or ethylenic dicarboxylic acids which are transformable to us form, which may be employed, include maleic acid (above described), fumaric acid, the mono or di chloro substituted maleic and fumaric acids, alkylated maleic and fumaric acids, such as itaconic, citraconic acid, mesaconic acid, mono and di phenyl maleic acid, benzyl maleic, dibenzyl maleic, ethyl maleic, or any similar acids containing a double bond in the chain between the two carboxyl groups.

It is preferred to employ the dicarboxylic and the oleflnic compound in approximately molar ratio though, of course, a certain degree of variation within the scope and spirit of the invention is permissible.

oxidizing agents such as benzoyl peroxide may be employed to speed up reaction of the resinforming materials. Reducing agents, such as hydroquinone pyrogallol, tannic acid, etc. may be employed to retard reaction.

As previously stated, the resinous bodies are insoluble, but it is possible to cast incipiently polymerized masses into moldsin which hardening to final form is efi'ected. Polymerization in molds formed of soft glass, Pyrex, or other material transparent to actinic rays is contemplated. Likewise, it is possible to introduce reactive mixtures containing at least a portion of irradiated material into opaque molds of rubbe or plaster and then to complete polymerization. It is also possible to heat the resins to the softening point and then to press themto shape.

A further application of the invention consists in providing a layer of polymerizable materials and plasticizer between two sheets of glass. By irradiating this glass, it is possible to form a film of transparent closely adherent resin between the glass sheets, thus forming a safety glass, The materials may be partially polymerized prior to application to glass. In a similar manner this class of resins may be employed in the lamination of wood, fabrics or other materials. Resinous bodies can be cut to any desired form and then polished to provide a great variety of articles. The resins and scraps of the resins may be shredded or powdered and then molded under heat and pressure, or the comminuted material may be mixed with further polymerizable material which by appropriate treatmentwill be converted into hard bonding resins. Oil-soluble dyes, such as Rhcdamin B, Victoria green and pigments such as titanium dioxide may be incorporated into the resins prior to final solidification.

The new resins may be employed in the formation of optical lenses, Jars, or lids for jars for cosmetics, drugs, foods and the like. They may be cast or cut to form an indefinite variety of handles, buttons, and objects of similar nature, or cast about specimens or objects of art to effect an embedment thereof. They may also'be used for the formation of panels and coverings for electrical apparatus of a great variety.

Application of the principles of the invention is illustrated by the following example:

Example I Grams Maleic anhydride 25 Styrene 35 Methyl levulinate 30 In the above example the mixture was preferably brought to a temperature suflicient to obtain mutual solution of the components, Polymerization was then efl'ected by irradiation with actlnic rays. The rate of polymerization was controlled by increase or decrease of the intensity of irradiation and/or the temperature. It can be brought to completion by irradiation with direct sunlight for a few minutes (15 or 20), followed by exposure to subdued light for some six hours. These exposures may take place at room temperature or slightly above, if so desired. The product may also be further hardened by heating.

But slight distortion takes place during polymerization. The resin is ofexceptional clarity and is not subject to change of color upon aging. All of these qualities combine to provide a resin par excellence for embedding specimens, such as insects, flowers and biological specimens. An object, such as a beetle can be introduced into a solution of styrene and maleic acid or anhydride containing a plasticizer in a container of suitable size and shape and the reaction to form the solid resin efiected, at temperatures sufliciently low to obviate damage to the specimen, merel by mild irradiation. There is no damage to the specimen, due to shrinkage and distortion of the medium during setting. The reaction is sufliciently rapid to be commercially feasible.

Example I! A sample of a solution from Example I was placed between two glass plates or soft glass and irradiated for one hour as described. The resin formed as a thin film between the plates which were not easily separated.

Example 111 I A portion of the solution of Example I was irradiated for five minutes until it had congealed to incipient gelation (the mass could still be poured). This enabled more of the material to be placed between the plates. During the second minutes of irradiation, pressure was applied to the plates. The finished plates adhered well and shattered with difficulty.

In the foregoing examples the dicarboxylic acids and their anhydrides are to be considered as equivalents, since each anhydride is derived from the acid merely by elimination of a mole of water and the ester is the same regardless of whether the acid or the anhydride is employed. Therefore, the term anhydride in the claim includes the acids and the term acid includes the anhydrides.

The embodiments of the invention herein described are merely exemplary and numerous modifications may be made therein without departure from the spirit of the invention or the scope of the appended claim.

Reference is made to applicants copending application Serial No. 395,062 filed May 24, 1941, and entitled Plasticized styrene-maleic resin composition.

What I claim is:

A clear and hard plastic composition consisting essentially of the conjoint addendum polymer of maleic anhydride and styrene in approximate- 1y molar ratio obtained by the polymerization of said components in about 10 to per cent, upon the basis of resin components of cyclohexanone which is retained in the composition as a plasticizer.

HOWARD L. GERHART. 

